1. Field of the Invention
This invention relates to cutting apparatus for cutting sheet materials, and more particularly to a rotatable cutter and a rotatable backup member for providing cuts that define a removable portion of the sheet, and means for removing the removable portion therefrom.
2. Description of the Prior Art
Rotary cutting apparatus is known from German Patent Publication No. 11 05 698. That known cutting apparatus can be used to make straight and stepped cuts in alternation in a continuously traveling tubular film so that tubular sections are cut from the film. The stepped cuts usually result in cut-out web sections, which must be removed from the apparatus in order to avoid disturbances. However, no means for removing such cut-out web sections are disclosed in that publication.
German Patent Specification No. 716,250 describes a cutting apparatus which includes cutter blades that are rigidly coupled to a shaft and spaced 180.degree. apart and serve to make straight and stepped cuts. The cutter blades cooperate in alternation with a grooved bar, which rotates at twice the speed of the cutter blades but at the same peripheral velocity. In that known apparatus a two-armed lever is pivoted to a rotating lever which carries the grooved bar, and one arm of the two-armed lever carries a needle for piercing the cut-out web sections whereas the other arm carries a cam follower roller, which rolls on a cam wheel. The extending and retracting motion of the needle is controlled by an eccentric segment, which is pivotally movable out of and into the orbit of the cam follower roller and is controlled by means of laterally disposed linkages and two-armed levers by an eccentric which is non-rotatably connected to the cutter shaft.
The cutting apparatus known from German Patent Publication No. 11 05 698 cannot be provided with the apparatus which is known from German Patent Specification No. 716,250 and that serves to remove cut-out web sections. This is due to the fact that because of the physical arrangement of the elements disclosed in German Patent Publication No. 11 05 698, involving the locations of the rotating grooved bars and cutter bars, and of the gears for moving the bars parallel to each other, there is no space available for accommodating such mechanism.